Process of producing alkali-earth metals



W. F. BLEECKER AND W. L. MORRISON.

PROCESS OF PRODUCING ALKALI EARTH METALS.

' APPLICATION FILED OCT. I9. i9l5- 1,31 1,378.

Patented July 29, 1919.

- INVENTORA.

MK By ATTO E'Ys' E SATESA 'FFIOE.

. WARREN F. BLEECKER AND WALTER L. MORRISON, O13 CAN ONSBURG, PENNSYLVANIA,

' ASSIGNbRS TO ELECTRIC REDNCTION COMPANY, A CORPORATION OF PROCESS OF PRODUCING ALKALI-EARTH METALS.

To all whom. it may concern: -Be it known that we, WARREN F. BLEnoKEn and WALTER L. MORRISON, both citizens of the United States, residing at Canonsburg, county of Washington, State of Pennsylvania, have invented certain new and useful Improvements in Processes of Producing Alkali-Earth Metals, of which the following is a specification.

Our invention relates to processes of producing alkali earth metals. The main object is to provide a simple, cheap and efficient process, by which such metals can be obtained in solid or liquid form, with great ease and rapidity. More specific objects will more clearly appear from the detailed description given below, taken in connection with the accompanying drawing, which illustratcs one form of apparatus for carrying out the process, and which forms a part of this specification.

While the invention is applicable to the production of various of the alkali earth metals, it is especially advantageous for the production of 'magnesiumin solid or liquid form. In order to illustrate our invention,

we will therefore describe in detail the process for the production of magnesium, which embodies our improvements in one-form.

We take magnesium containing material, preferably magnesium oxid containing material, such as magnesite or dolomite and if the materials have not already been suitably calcined, they are then placed in a reverberatory furnace and heated, so as to remove moisture therefrom and to breakup any carbonateszwhich may be present and so remove deleterious oxidizing components therefrom. With this calcined material in crushed form we mix a suitable reducing agent, preferably a metalloid reducing agent, such as crushed silicon or granulated metallie aluminum, or both. By the term metalloid reducing agent, we mean a reducing agent or agents formingfusible slags which are substantially unvolatilized or undecomposed at the-working temperature of the. furnace and which are capable of not only depriving magnesium of oxygen at a temperature above 1200" C., butlikewise are capable of retaining oxygen in the slag at a temperature below 1200 C. Under certain circumstances, other reducing agents maybe used. The reducing agent is mixed Specification of Letters Patent.

with the magnesium oxid containing mate.

nesium oxid or its equivalent, calcium oxid,

preferably partly both, to promote fluidity when the mixture is later reduced to molten slag. 5 to 10 per cent. (of the total alkali earth oxid) of fluorspar CaF or silicon,Si, may also be added to thin the slag and make a better'flux, especially if aluminum is used the reducing agent. If silicon is used it promotes the fluidity of the resultant slag and it may be used more or less without special flux or used with aluminum to improve the fluidity of the slag. The mixture, preferably hot, is then transferred or fed to an electric furnace, preferably alternating current, in which it is fused. The voltage of the electric furnace will, of course, vary with Patented July 29, 1919.

Application filed- October 19, 1915. Serial No. 56,734.

the nature of the slag, 810., but in some instances, we have found a voltage in the neighborhood of 40 or 50 volts suitable. The

electric furnace is preferably of the conduct:

ing hearth type with the bottom or Wall of the furnace forming one electrode, while the other electrode or electrodes are adapted to have their ends immersed in the molten mixture or bath. The bottom or wall of the furnace, which forms one electrode, is preferably constructed of magnesite brick (although carbon material may be used) with suitable metallic contacting members leading thereinto. The current passing from one electrode to another heats the mixture and fuses it. We have found in certain mixtures a temperature of 1300 to 1500 C. is suflicient to produce a molten mixture. Due to that is, suddenly chilled, the magnesium vapors condense to form a fine powder, mostly impalpable and of dark color, having generally the characteristics that it is incapable of being fused together to form a liquid and be cooled before removing it from the neuthat it is amorphous and nodular in form and has superficial impurities. By condensing them quickly, in this way, if there is any carbon monoxid present in the gases, there is a tendency to prevent it reacting with the magnesium, causing the magnesium to be changed back with the oxid. If the volatilized magnesium is cooled slowly in a suitable atmosphere, it collects in an agglomerated form, rather than in the form of a fine powder.

The operation may be made substantially continuous, fresh portions ofthe mixture from the reverberatory or preheating furnace being fed either continuously or from time to time into the electric furnace, and the condensed magnesium or other I alkali earth metal being removed either continuously or from time to time, from the con is free from air or..its constituents, and contains as little as possible of carbon monoxidv or other gas readily decomposed or acted upon by magnesium or its vapors. The atmosphere should be substantially non-oxidizing. This may be done by either driving the electric furnace so rapidly that some magnesium vapor is expelled, orielse by pro- .viding a working atmosphere of hydrogen or other inert gas. Preferably a combination of the two methods is employed, in the sense that the apparatus issupplied with sufficient inert gas, such as hydrogen, to avoid a material loss of magnesium vapor and at the same time, without permitting air to be suckedin at the condenser outlet.

With some of the reducing agents it may be desirable to reduce the pressure of the atmosphere as to render it substantially inert, but avoiding the use of a vacuum. The-magnesium, particularly when con-' densed in theform of a fine powder, should tral atmosphere to such an extent as to prevent any rapld surface oxidation thereof,

which would causethe powder to heat up, and superinduce active combustion thereof. We preferably cool it below 40 0., before removing it from the neutral atmosphere. It may, however, beremoved from the condenser and put into any suitable receptacle, even before being so cooled, by keeping it -in a neutral atmosphere during-such transfer.

In the drawing'Fig. 1 illustrates diagram- .inatically, and largely in section, an apparatus adapted to carry out the improved process, and Fig. 2 is an end view of the condenser shown in Fig. 1.

Referring to the drawing,,1' represents the preheating furnace, which is of the re- 7 verberatory type, the hot gases being intro: duced at 2, below the hearth 3. The alkali earth containing material is introduced through a hopper 4 on the hearth 3. The

hot gases pass up around wall 5 and heat the materials, after which the gases pass out through a stack 6. :'A suitable conveyer 7 .is provided for gradually moving the materials along the hearth 3 and out into the hopper 35, wherein they may be mixed with the reducing agent. rentelectric furnace is shown at 8', having its inner walls lined with magnesite bricks 9, which contain oneelectrode of thefurnace, this being shown as a series of iron pins or rods 10 which project, up into the The alternating cur lin ing..9, these pins being connected with I common iron conductor 11, which, in turn,

is connected to a copper conductor 12. An opening 14 is provided at the bottom of-the furnace, from which the slag may be tapped,

as desired. The otherelectrode is shown at 13, and may be a rod of graphite orother suitable material. The electrode '13 is inserted through the top ofthe furnace and is surrounded by a water jacket 15, through which water is circulated by means of inlet andoutlet pipes 16. Above the jacket 15 a ring 17 surrounds the electrode, which ring is packed with asbestos packing 18,in order that the furnace may be made substantially air-tight.

The hopper 35 discharges into a chute 19, which enters the electric furnace substan-' tially below the surface of the bath, which surface is indicated inthe drawing by the line 20. In order that the mixed materials may be conveniently injected into the bath, chute 19 is provided with a reciprocating plunger 21, operated from any suitable source of power, so as to push the material from the chute-19 into the molten bath, as desired. The 'end of electrode 13 is .immersed in the bath 20, so that both electrodes of the furnace arein contact with the molten bath. In this way the heating action'is due largely to the resistance of the bath to the current passing therethrough 1 20 rather than to an are between the bath and electrode 13, so that a more uniform and desirable heating action is produced. The outlet of the electric furnace for the vapors and gases. is shown at 22. This leads 'dlrectly to a horizontalcondenser 23, oval in cross section, as shown in Fig. 2, al-

though, if desired, the top or wall of the furnace or othersuitable surface may be used. In the form shown, ithere extends 150.

bodiment thereof, we -do not demre .to be without departingfrom metallic. magnesium:

centrally along the top of condenser 28, acold water pipe 24, '"which discharges cold water on top of the mndenser in such man-. ner'that it. runs down over both sides thereof. The lower half of the condenser is inclosed by a water jacket 25, andthe water running down over the outer surface of thecondenseris collected inthis water jacket and may overflowtherefrom through an outlet pi 26. The condenser may be pro-. v1ded with an outlet for gases or vapors at 27, a.nd an outlet for. the condensed magneslum or other alkali earth metal at 28, or the may also'be forced to" exit through the outlet 28. ,In order that. the condensed magnesium may be easily. removed through the outlet 28, a worm or' screw 29 is pro; vided, which may be turned by handle 30, soas to force the material alon the bottom of the condenser to andthrou the'outlet 28. The material may be allowed to fall. nto cans orother receptacles, one .of. which 1s shown at 31. These receptacles ma be provided gas inlets 32, through w 'ch inert gas may be injected in order to' fill the receptacle with gas,- so' that when the condensed magnesium is deposited in the receptacle, there is no den of rapid surface oxidation thereof, y observing or testm' the gases which-flow from the exit 27, 1 any, 1t may be determined whether .the' condensing action is suflicient. In order to makesure that the atmosphere in the furnace and condenser is non-oxidizing, and I to keep the furnace and atmospherefree from a r or its constituents, inlet pipes 33 and 34 maybe provided, through either or both of which hydrogen or other inert gas may be lnjected intothe furnace and condenser in an amount suflicient to prevent any material amount of air being sucked in through the outlet 2-7, by reason of the suctlon reduced by the condensing action.

Alt ough we have explained our invention m great detai-L-with respect to one em- -limited to such details, as man changes and modifications may be: ma therein tligfiirit and scope of our invention in its b er aspects, as for the condenser may be so operated as to deliver fluid metal.

- Ha'vingdully and-clearly described our improvements,;,what We claim as new and des re to secure by Letters Patent is:-J

1.' 'l'-he improved process of producing in esiumwhich consists in heating magnesiumoxidwith areducingyagent to produce .magnesium vapors and conde 'ng' them in an inert atmosphere to pro. ce

2. The improved "process-of producing magnesium which consists in heating magnesium oxid with a metalloid reducing'agent I to produce magnesiumvapor and condens sium.

liquid state.

mg nesium.

3. The improved process of alkali. earth metals which consists in heatmg. the oxids thereof in the presence of a reducing agent to roduce alkali earth h v por to produce metallic producing 1 metal vaporsand con ensing them in a noncontaining alkali earth metal oxid or oxids. to, remove moisture and decompose carbonates, if present therein, then further heating to volatilize the alkali earth metal and condensing the volatilized alkali earth metal to the solid orliquid state.

6. The process of producing alkali earth metals which consists in heating material containingalkali earth metal oxid or oxids to remove moisture and decompose -carbon-- ates, if present therein, then further heating the material with a metallold reducing agent to volatilize the alkali earth metal and condensing the volatilized earth metal in an inert atmosphere to the solid 0l7liqi lid state.

the material with areducing agent he process of producing magnesium I 'which consists'in heating magnesium oxid containing material, to remove moisture and decompose carbonates, if present, then further heating the material in the presence ofa reducing agent to volatilizethe magne-- sium and condensing the magnesium vapor so volatilized 8.. The process of producing magnesium which consists in heating magnes1um oxid containing material, to remove moisture and decompose carbonates, if. present, then to produce metallic magnefurther heating the material in the presence I "ofa metalloid reducing agent to volatilize the magnesium and condensing the magnesium vapor so volatilized to producemagna sium in a solid or liquid state,

.9. The

which consists 'in heating magnesium oxid.

process of producing magnesium containing material to remove moisture and decompose carbonates, if present, then sium and condensing the magnesium vapor fur- I ther heating the material in the resence of a reducing agent to volatlllze-t e magne-- pliers, to produce magnesium in a solid or 10'. The process producing magnesium .taining magnesiummxid to remove moisture therefrom and decompose oxidizing substances, then heating a m' ture of the magnesium oxid contaiiring material. and a state.

11. The process of producing alkali earth metals which consists in heating a mixture of alkali earth oxid containing material to therefrom, then cooling the vapors to pro:

metals which consists in heating a mixture remove moisture-and decompose oxidizing substances if present -therein,:then fusing and reducing the material at a tem rature sufiiclentto volatilize alkali eart metal uce the alkali earth metal in a solid or liquid state.

12. The process of producing alkali earthv of alkali earth oxid containing material to remove moisture and decompose oxidizing substances, if present therein, then heating the material in the presence of reducing agent to atemperature suflicient to volatilize alkali earth metal therefrom, and then cool-- pors t erect and then "condensing the vapors to produce the alkali earth metal in a solid f or 1 e magnesium 'phere toproduce the alkali earth ing the vapors in a non-oxidizing atmosrnetal in a solid or liquid state. I v

.13.. The procjssof roducin alkali earth metal from compoun thereo which consists in reducing and heating a compound thereof in an unevacu'ated atmosphere sufiicientl to volatilize the metal to form vaquid state.

14. The process of producing alkaliearth metal which consists in fiuxing and reducing an oxid thereof to separate the oxygen from the metal and collecting the metal in a solid or liquid state.

. 15. The im roved process of producing magnesiumw ich consists in fluxing amag: neslum oxid containing .material in the presence of a reducing agent to separate the from its oxygen and collecting the ma esium in solid or liquid form.

16,. he process ofiproducing alkali earth 1 metal which consists in fluxing and reducin' a material containing the metal and vb atilizing the metal to produce vapors thereof and then cooling the vapors so quicklyas to produce the metal in a solid statein the form of a fine powder.

- 17. The process of producing magnesium which conslsts in fluxing and reducing magnesuun oxid containing material, to. volatilize the magnesium and produce vapors thereof and then cooling the vapors so rapidly as to producethe 'agnesium' in a so id state in the form of a fine wder.

metal. whic fluxing' a material 1 metal to p metal. which consists in terlal in a furnace ina non-oxidizing at-" duc' '18. The recess of producing a ali earth 7 containing an oxid of themetal and mealloid redu'c' agent and volatilizin the phere so quickly as to produce the metal in a solid state in the form of a fine powder.

' 19. The process of producingalkali earth fusing an alkali earth metal compound, by means of an electric current with the material forming part of the electric circuit, to fluxaway the other constituent of thecompound. and separating the metal constituent to produce the metal in solid or liquid form.

20. The, pr of producing alkali earth metal which consists in uce vapors thereof an then cooling the vapors in a non-omdizing atmos- 4 fusmg. an alkali earth metal oxid containing material, in the presence of a reducing agent, and slagging away the combined 0 gen and separatmg the metal in solid or hquid form."

21.. The process of producing magnesium which consists in fusing magnesium oxid in the prnce of a metalloid redu agent by means of. an electric current wit the material forming part of the electric circuit to produce metallic magnesium vapors and then condensing the vapors in a non-oxidizing atmosphere to produce metallic magnesium in a" solid or liquid state; 22. The process of producing alkaliearth metal which consists in and reduc-- an alkali earth metal containing mamosphere, to volatilize the metal and produce vapors thereof and then condens' the vapors to reducethe metal to solid or hquid it non-oxidizing atmosphere to reduce the metal to solid or liquid form.

24. Th which consists in fusing magnesium oxid magnesium and con ensing the vapors in e process of producing magnesium,

recess of 'produci ng alkali earth to volatilize the metal and producevapors thereof, and then condensing the vapors in in the presence of a reducing agent in a.

non-oxidizing atmosphere to vaporize the 7 a non-oxidizing atmosphereto produce. me- I tallic magnesium. q I.

- 25. The recess-of producing alkali earth metal whic consists 1n reducmg and'heat- I ing. a material containing a compound thereof sufliciently to volatilize the metalto form vapors thereof and then condensing the va-- rs in a non-oxidizing atmosphere to rouce the alkali earth metal in a soli or liquid state.

metal, which consists in fluxing and -reor, vo atilizing the metal to produce-vapors l I 126 26. .The process of producing alkaliearth a material-containing an oxid. thereandcondensing the vapors in a mm 130 oxidizing atmosphere to produce the metal in a solid or liquid state. 7

27. The process of producing alkali earth metal which consists in reducing and using an alkali earth metal containing material, by an electric current with the material participating in the electric circuit to volatilize the metal to produce .vapors thereof and then condensing the vapors to produce the metal in solid or liquid form.

28. The process of producing alkali earth metal which consists in fusing an alkali earth metal oxid containing material, in the presence of a reducing agent by an electric current with the material participating in theelectric circuit to volatilize the metal to produce vapors thereof, and then condensing the Vapors to produce the metal in solid or liquid form.

29. Theproeess of producing alkali earth metal which consists in reducing and fus- -ing an alkali earth metal compound and slagging away the other combined constituent of the compound and separating the metal constituent to produce the alkali earth metal in solid or liquid form.

' 30. process of producing'alkali earth 7 metal which consists in reducing and fus ing an alkali earth metal compound and slaggmg away the other constituent of the compound and separating the metal constituent in .a hydrogen atmosphere to produce the alkali earth metal in solid or liquid form.

31. The process of producing alkali earth metal which consists in heating and reducing a material containing alkali earth metal to volatilize'the metal and condensing the same in a hydrogen atmosphere.

32. The process of producing alkali earth metals which consists in heating alkali earth metal and oxygen combined containing material to remove moisture and decompose oxidizing substances therein and fiuxing and reducing the material to separate the oxygen 

